Cancer of the prostate is the most prevalent malignancy in adult males, excluding skin cancer, and is an increasingly prevalent health problem in the United States. In 1994, it was estimated that in the U.S., 38,000 deaths resulted from this disease, indicating that prostate cancer is second only to lung cancer as the most common cause of death in the same population. If diagnosed and treated early, when the cancer is still confined to the prostate, the chances of cure is significantly higher. Accordingly, there is a great need for sensitive methods for the detection of organ-confined prostate cancer.
Extracellular Phospholipase A.sub.2 (PLA.sub.2) enzymes appear to mediate a variety of responses including cellular proliferation, chemotaxis and inflammation. There are two major groups of extracellular PLA.sub.2 enzymes: pancreatic or group I and rheumatoid arthritis synovial fluid (RASF) or group II. The group I enzyme functions in digestion and also in modulating proliferation and chemotaxis. Currently, RASF-PLA.sub.2 is predominantly thought to play a role in inflammatory responses including arthritis, septic shock and lung injury. The level of RASF-PLA.sub.2 is regulated at the mRNA level by a variety agents including interleukin-6, interleukin-1 and tumor necrosis factor, all of which are involved in inflammatory responses. While elevated levels of PLA.sub.2 enzyme activity have been reported in a prostate cancer tissue in rats (F. H. Faas et al., The Journal of Urology, Vol 156, 243-248, 1996), there do not appear to be any reports of alterations of RASF-PLA.sub.2 mRNA or polypeptide level in prostate cancer or benign prostate hyperplasia in humans.
Northern blot analysis was done on equivalent amounts of mRNA isolated from prostate cancer (PC), benign prostatic hyperplasia (BPH) and normal prostate (NP) according to methods published in Maniatis (MOLECULAR CLONING Maniatis, et. al., Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.). Probe was synthesized from the full length cDNA encoding RASF-PLA.sub.2. Results indicated the following ratios of RASF-PLA.sub.2 mRNA: 10:0.25:1 for PC, BPH and NP, respectively. Loading differences were normalized using actin mRNA levels. The result showed that RASF-PLA.sub.2 appears to be upregulated in prostate cancer and potentially downregulated in BPH.
As used hereinbelow "PLA.sub.2 " refers to group II or RASF-PLA.sub.2.